In contrast to the discussion of similarities in many articles that have been published, most of these posts were rather sceptical and reserved, emphasizing the importance of being extremely careful when using analogies to justify methodological transfer across disciplines. Despite this general scepticism, that I mentioned myself, I am still convinced that methodological transfer can be fruitful when carefully adapting methods to the needs of the target discipline — and we know that this has been done in both directions in the fields of biology and linguistics.

Apart from the problem of adapting methods from other disciplines, one important question is, how to identify fruitful analogies in the first place. As a visiting post-doc in the bioinformatics research group Adaptation, Integration, Reticulation and Evolution, led by Eric Bapteste and Philippe Lopez (UPMC Paris), I have discussed this question a lot during the past one and a half years.

We came up with the idea that it might be useful to restrict the range of potential analogies one might draw between biology and linguistics by concentrating on analogies between processes. Taking processes, rather than research objects, as a starting point comes closer to general approaches to analogy, which usually claim that the core of analogy is similarities of functions (Gentner 1983). By applying this principle to compare aspects of linguistic and biological evolution, we were able to identify some potentially fruitful analogies that could lead to novel approaches, not only in linguistics but potentially also in biology.

Among these are specific processes of divergence (like incomplete lineage sorting in biology, which is very similar to dialect chain dissolution in linguistics), specific introgressive processes (like protein assembly, which shows some striking similarities with word formation), and specific systemic processes (like constructive neutral evolution in biology, providing an explanation for convergent evolution in languages resulting from common descent, also called drift or Sapir's drift). On the other hand, we also found that many processes are most likely to be unique to one of the disciplines, including such processes as sound change in linguistics and natural selection in biology.

These reflections have been summarized in a paper titled "Unity and disunity in evolutionary sciences" which was published at the beginning of this week (List et al. 2016, PDF here). I will not go into further detail of the specific new analogies we proposed, but instead recommend those who are interested in the issue to read our paper (and potentially discuss the issue of analogies further with us).

Since the identification of potentially fruitful, new analogies between biology and linguistics is just a starting point for a closer investigation of the suitability of methodological transfer in practice, I am quite optimistic that I will follow up on the new analogies mentioned above in more detailed future blog posts.